When a secret plan or scheme to accomplish some purpose in a storyline of a TV show or movie is so absurd, preposterous, or silly that it is unworthy of serious consideration.
Usually leads the viewer into a fit of yelling at the movie/show, sometimes throwing things in frustration.

"So the Joker really arranged a big truck chase just so that he could get caught and go to prison, then he could kidnap a guard and grab his phone to make the call to set off the bomb he'd previously sewn inside the henchman in the next cell? That's ploticulous."